One technique of surface or land wellhead production includes drilling a well bore on land and installing a string of conduit or casing in the well. The first string of conduit is typically referred to as conductor pipe that may be lowered near the surface into the well hole drilled into the formation. The conductor pipe is then typically cemented in place with an upper portion extending above the surface. The upper portion of the conductor pipe extending above the surface may be housed in a cellar constructed around the well bore. The outer diameter of the conductor pipe may be sealed against a cellar base. The conductor pipe is typically used to prevent the sides of the well bore from caving in. The conductor pipe may also be called a drive pipe that is typically short in length and sometimes driven into the ground.
Once additional well operations are required, such as installation of additional casing within the well, the upper portion of the conductor pipe is typically cut at a desired point and leveled off. A support or landing ring is then typically installed on top of the conductor pipe. The landing ring can receive a fluted mandrel hanger that may support casing in the wellhead and allow drilling fluids or cement, during cementing operations, to return upwards through the hanger's flutes. The landing ring and fluted mandrel hangers are commonly used in surface wells. After cementing, a pack-off bushing may be installed above the fluted casing hanger to seal off the flutes.
A diverter adapter may also be connected to the conductor pipe. The adapter typically has slips at a lower end that can engage the outer diameter of the conductor pipe at a point below the installed landing ring.
Due to loss of cement circulation during cementing operations, sometimes topping up cement through the radial space between the landing ring and fluted mandrel hanger is necessary. In some cases, the radial space between the landing ring and hanger is not big enough to allow cement tubing, commonly know as “wash” piping used in such topping up operations to run through. Therefore, topping up cement requires more work and takes more time. Occasionally, the well is abandoned if the cement bonds poorly. Typically, the space between the mandrel hanger and the landing ring does not allow for anything other than small coil tubing. To try and prevent this and allow for larger cement tubing, a larger size casing and larger landing ring can be utilized to provide additional clearance and allow cement topping up. Also, a side entrance may be formed in conductor to do cement topping up. These techniques however, dramatically increase cost.
An improved technique for topping up cement without the need for larger casing is therefore desired.